Comparative Vegetative Anatomical Study of the Genus Garcinia L. (clusiaceae / Guttiferae) in Sri Lanka

Vegetative anatomical studies of 10 species of Garcinia L., described by earlier workers to be present in Sri Lanka were carried out. A detailed anatomical investigation of lamina, petiole, young stem and wood, was carried out and the results were analyzed by statistical methods. The study agrees with previous workers in that there are 10 Garcinia species in Sri Lanka. Further, it also revealed that the boundaries between the Sri Lankan species could be successfully established based on vegetative anatomy. With the results of anatomical, morphological and ecological studies combined with statistical analysis, possible evolutionary relationships between the nonendemic and endemic taxa has been suggested. On this basis, the non-endemic species, G. mangostana L., G. spicata (W. & A.) Hook. f. and G. xanthochymus Hook. f. centering G. morella (Gaertn.) Desr., form the basic stock from which two lines of specialization have arisen. The doubtful endemic G. echinocarpa Thw. could be considered as the most specialized species and the two endemics, G. quaesita Pierre and G. terpnophyla (Thw.) Thw. could be the coupling group between the basic group and G.echinocarpa Thw. The endemic G. zeylanica Roxb. is observed to be an off shoot of G. quaesita Pierre. The exotic species G. xanthochymus Hook. f. could be interpolated between the basic group and the group which includes the two endemics G. thwaitesii Pierre and G. hermonii Kosterm. Further, based on the overall anatomical data, results of statistical analysis, ecological distribution and the findings with respect to the degree of specialization, it could be suggested that the most specialised species, G. echinocarpa Thw., is endemic to Sri Lanka.